Latch tripping mechanism comprising abutting pivoted members



Dec. 4, 1951 J. F. cHlPMAN LATCH TRIPPING MECHANISM COMPRISING ABUTTINGPI VOTED MEMBERS 2 SHEETS- SHEET l Filed May 8, 1950 DCC. 4, 1951 J. F.cHlPMAN LATCH TRIPPING MECHANISM COMPRISING ABUTTING PIvoTED MEMBERS 2SHEETS- SHEET 2 Filed May 8, 1 950 Patented Dec. 4, 1951 LATCH TRIPPIN GMECHNISMv COMPRISING ABUTTING PIVOTED MEMBERS John F. Chipman, SouthWeymouth,- Mass., assignor to Allis-Chalmers Manufacturing Company,lMilwaukee, Wis.

Application May 8v, 1950, Serial N0. 160,652

(CL I4-2) 7 Claims.

This invention relates generally to operating mechanisms for electriccircuit breakers which are latched closed against an opening biasingforce, and more particularly to tripping'means for unlatching andcausing opening of thecircuit breakers by the biasing force. y

Circuit breakers of this general type, and particularly multipolecirculit breakers which are designed to interrupt heavy currents, are ofrugged construction and usually employ strong springs lto operate thecontacts between closed and opened positions. The tripping device whichcooperates with a releasable contact operating structure for normallylatching a releasable member must be designed to withstand considerablestrain because it absorbs part' of the force of the contact operatingsprings when it unlatches the releasable member.

Tripping devices heretofore provided have been designed as a unitarystructure', and' the reactions of the contact operating mechanism duringan unlatching operation have resulted in the creation of a givenexcessive amount of kinetic energy which must be absorbed before thetrippingdevice comes to rest. If` the weight of the tripping device weresubstantially decreased. to reduce the kinetic energy resulting from themovement thereof,.the device would not be able to stand the forceVtransmitted to it from the contact springs.v

In accordance with the invention claiined'a new and improved trippingdevice is provided comprising a pivoted force receiving member and apivoted force transmitting member. The force transmitting member uponmovement thereof actuates the force receiving member to move a latch torelease a member which operates a contact vactuating structure. Uponrelease of the contact actuating structure, the force receiving memberis further actuated -in latch releasing direction by the contactactuating springsindependently of the force transmitting member.

.The force transmitted to the tripping device by the contact actuatingsprings results inraccelerating only a part of the tripping device andconsequently the resultant kinetic energyproduced is less than thekinetic energy produced by the unitary tripping devices heretofore used.

It is', therefore, one object ofA the-presenty invention to provide anew and improved tripping device for unlatching electric circuitbreakers in which a pivoted forceV receiving. member is divorced duringactuation of the:V tripping device from a pivoted forcetransmitting'm'ember;k

`Another object of thiszinventioniis.tofprovide a new andr improvedtripping device for electric circuit breakers in which a pivoted forcereceiving member and a pivoted force transmitting member cooperate tomove together during an unlatching operation, but move independently ofeachother aiter the unlatching operation.

vA further object of this invention is to pro'- vide a new and improvedtripping device for electric circuit breakers in which a pivoted forcetransmitting member actuates a pivoted force receiving member uponactuation or' the tripping device and arcing Contact springs furtheractuate the force receiving member upon move-'- ment oi' the arcingcontacts thereof.

Objects and advantages other than those set forth will be apparent fromthe following description when read in connection with the accompanyingdrawings in which:

Fig. 1 is a sectional View of an operating mechanism embodying thepresent invention;

Fig.`2 is an enlarged sectional View of a part of thetripping deviceillustrated in Fig. l taken alongline 11F-'II in Fig 3;

Fig. 3 is airont view ofthe embodiment illustrated in Fig. 2 with partofV the elements removed; and

Figs: 4k to 6 show in cross-section three dierent positionsA of thetripping device and associated linkage by which the circuit breaker isoperated and restrained' in closed circuit position.

Referringmore particularly to the drawing by characters oi reference,Figs. 1 to 6 illustrate part ora magnetic blowout type circuit breakerIl' andan operating mechanism i2. The latter comprises a iorcetransmitting structure I3 and a tripping means iii'. Although circuitbreakers of the `type herein considered are frequently provided with aplurality oi" similar pole structures, one for each phase of a polyphaseelectric circuit',l only one such pole structure or pole unit isshowninFigs. 1 to 6 and the circuit breaker will be described in detail as ifit were of the single pole type.

Circuitfbreaker il illustrated in Fig'. l/inclu'des as elements thereofa pair of terminal studs l5 (only one of. which is shown) for connectingthe circuitl breaker to line conductors (not shown). Breaker lf-Icomprises essentialy meansfor open- Ving the Vcircuit to form an arc,and an arc extinguishing structure.r Specifically, the circuit openingmeans comprises a ixed arcing` contact I6 and a movable arcing contactH. Arcing contact Il is mounted ona lever i8 which is pivotal-ly mountedat I9 on an extension arm 20 of one-Cof thel circuit breaker studs (notshown) 3 and is operated by means of a connecting rod 2l of insulatingmaterial forming a part of the force transmitting structure I3 foroperating the movable Contact between closed and open circuit positions.Fig. 1 illustrates the movable arcing contact I1 in the closed circuitposition.

For the purpose of interrupting the arc formed upon separation of thearcing contacts, an arc extinguishing structure, such as an arc chute 24(partly shown in Fig. 1) is mounted directly above the arcing contactsso as to receive the power arc when it is driven upward by a magneticblowout means 25. The arc chute is disposed directly above the arcingcontacts, as shown, when the blowout means act upward, but may bemounted in any other suitable location when the blowout means act inother directions. The arcing contacts and the magnetic blowout structurecan assume any suitable known form so that a brief description thereofwill be sufficient. The magnetic blowout means 25 comprises a core 26,poles 21, and a coil 28 which is inserted in the connection between theterminal stud I5, contact I6 and an arc runner 29, so that the arccurrent (as the arc travels along the runner) flows through the blowoutcoil in a manner well known in the art. Core 26 and .poles 21 embrace atleast part of arc chute 24 for driving the arc into the chute and towardthe exhaust end thereof.

The operating mechanism I2 illustrated is interposed between a solenoid36 and the movable arcing contact I1. In the position shown in Fig. l,the circuit breaker is in the closed position and the operatingmechanism is held in such vposition by a pivoted locking latch 3lforming a part of tripping means I4 and a tripping linkage or toggle 32.

In addition to toggle 32 comprising links 35 and 36, the mechanismcomprises a spring 31 which resiliently biases one end of link 35 to aframe 38. A bell crank 39 pivotally mounted to frame 38 at a point 40has one arm thereof pivotally connected to link 35 and the other armthereof pivotally connected at a point 4I to a connecting rod 42. A bellcrank 43 is connected to rod 42 and to a connecting rod 2I.

A contacting actuating spring lmeans 45 is compressed between frame 38and a collar 41 secured to one end of a connecting rod 46. The other endof rod 46 is pivotally connected to bell crank 39 at a point 4I, wherebya force transmitting structure I3 is completed between spring means 45and contact lever I8.

Tripping means I4 comprises a force receiving member and a forcetransmitting member to move latch 3I to release toggle 32. The forcetransmitting member comprises a trip bar 48 of U-shaped cross sectionmore clearly shown in Fig. 2. Trip bar 48 is provided with a bore 49engaged by a screw 56 which is surrounded by a helical biasing spring I.Trip bar 48 forms an integral part of a structure comprising two lateralplates 54 and 55 (more clearly illustrated in Fig. 3) which arepivotally supported by a shaft 56. Plates 54, 55 may havea running fiton shaft 56, which may be if so desired supported for rotation inbearings (not'shown) mounted on frame 38. The two plates 54 and 55 areeach provided with a hole 51 which minimizes their weight. Plates 54 and55 are rigidly interconnected by a tie bar 58.

The force receiving member of tripping means I4 comprises a block 59 inthe shape of an irregular hexagon pivotally supported on shaft 56. 1

.for controlling Vlatch 3I. ,mounted on one arm of a bell crank 68,which 4 thus are supported for pivotal movement about a common axis. Thelower surface of hexagonal block 59 abuts against tie bar 58, whichinterlocks the force transmitting and receiving members. Block 59 isprovided with a pin 60 against which a rat-trap spring 6I rests.Rat-trap spring 6I biases hexagonal block 59 in the counterclockwisedirection into engagement with tie bar 58, thereby interlocking theforce transmitting and receiving members during movement thereof inlatch releasing direction. Block 59 is provided with a pair of extensionplates 62 which are rigidly secured to and form an integral part ofblock 59 and serve as a bracket for a supporting pin 63. Pin 63 supportsa link 64 which cooperates with plates 62 to form a toggle A latch roll61 is is secured to shaft 56 if the shaft is rotatable. The other arm ofbell crank 68 is connected to link 35 through a pin 69. Latch roll 61 ofthe tripping means I4 is normally held in position by latch 3I. Theposition of bell crank 68 in turn determines the position of toggle 32.The force component transmitted from latch roll 61 to the latchingsurface of latch 3I is substantially normal to the latching surface andpasses through the center of pin 66 around which latch 3I pivots. Latch3I is held in position by link 64.

A toggle roll 10 isrmounted on a pin which 'interconnects links 35 and39 of toggle 32. Toggle roll 10 is arranged to move along surface 1I offrame 38 during the unlatching operation, thereby positioning toggle 32so that it may jackknife under the force of spring 45.

Solenoid 12 comprising coil 14 and armature 15 is provided for reclosingcircuit breaker II. Upon actuation of solenoid 12, armature 15 applies aforce to toggle roll 1U and moves toggle 32 to its over center position.For manual closing, the closing force is applied on link 35 by means ofbell crank 16, the rotation of which is controlled through a link 11attached to end of manual closing crank 18 located at the front of thebreaker. A latch check switch (illustrated in Fig. 2) needed forcompletion of the reclosing solenoid circuit is actuated by cam face 8Iof the hexagonal block 59.

The actual tripping operation is best illustrated in Figs. 4 to 6wherein Fig. 4 illustrates the circuit closed position of the operatingmechanism I2, Fig. 5 an intermediate position of operating AmechanismI2, and Fig. 6 the open position of v59 resting on tie bar 58, whichinterconnects lateral plates 54 and 55, is also rotated clockwise uponclockwise movement of lateral plates 54 and 55 to break the toggle 62,64. The breaking of toggle 62, 64 and the subsequent counterclockwiserotation of latch 3l releases the latch roll 61 of the restraining bellcrank 63. Latch roll 61 rides out of the notch in latch 3I and is forcedupward with toggle 32 by the reacting force of spring 45 acting on bellcrank 39. Toggle 32 moves upward into the position shown in Fig. 5,thereby completely releasing spring 45 which instantly separates thearcing contacts.

Upon release of latch roll 61. from the notch of latch 3| the forcecomponent transmitted from gettate latch roll 6,1 to latch U31-accelerates the unit comprising block 59, extension plates 6 2, pin 6?,`link 69; and*A latch 3i, thereby..unlocking the." force transmitting andreceiving-,meansg vThis force component being directly-proportional tothe size of spring l5 and the degree to which it is compressed is ofconsiderable magnitude and results, therefore, in a very highacceleration' offthe force receiving member ofV tripping device I4.

In accordance with the inventionV the force receiving member of trippingmeans i4 ifsdivorced from the force transmitting member, and thereaction which is transnfiitted-v from the latch to the other parts ofthe forcereceivingmember is not transmitted from the latterto the-forcetransmitting member. The force receiving-member is free to rotate in theclockwise orlatch opening direction under thevaction ofI the latchreaction without aiecting the force transmitting member, and the membersreach the position thereof shown inA Fig. 5. Because the forcetransmitting member is divorced from the force receiving member, themass of the force receiving member may be much smaller than heretoforeused, resulting in a substantial decrease of the kinetic energy thatwill be imparted to it, a reduction in the stresses imposed on thetripping device it, and an increase in the over-all speed of operationof tripping devices i4.,

While toggle 32 kmoves upWardr0ll 'lll thereof 'rolls along surface 'liof `frame 38 until toggle 3Q reaches the over center position andcollapses into the position shown in Fig. 6 through the biasing actionof spring 31. Upon deenergization of solenoid 3l), the forcetransmitting and receiving members of tripping device I return to theiroriginal position as shown in Fig. 6 through action of rat-trap spring6l.

. Although `but one embodiment of the presentY thereof connected to saidstructure, spring meansV for causing collapse of said toggle andactuation of said structure, means including a latch for preventingcollapse of said toggle, and means for actuating said latch to releasesaid toggle l'comprising a pivoted force receiving member and a pivotedforce transmitting member, said force transmitting member upon movementthereof actuating said force receiving member to move said latch torelease said toggle, said toggle upon release thereof further actuatingsaid force receiving member in latch opening direction independently ofthe movement of said force transmitting member.

2. An operating mechanism comprising a force transmitting structure andtripping means controlling said structure, said tripping meanscomprising a collapsible toggle having one link thereof connected tosaid structure, spring means for causing collapse of said toggle andactuation of said structure, 4means including a latch for preventingcollapse of said toggle, and means` for actuating said latch to releasesaid toggle transmitting structure land tripping means controllingsaidstruc'ture, said tripping means comprising a collapsible togglehaving one link thereof connected to said structure, aiirst spring meansfor causing collapse, of said toggle and actuation of said structure,'means vincluding a latch for preventing collapse of said toggle, andmeans for actuating said latch to releasesaid toggle comprising apivoted force receiving member, a pivoted force transmitting member, anda second spring means for biasing said force transmitting membertointerlock with said force receiving member during movement together inlatch releasing direction, said toggle upon-reflease thereof unlockingsaid members and further actuating saidforce receiving member in latchopening direction independently of said force transmitting member.

' 4. An operating mechanism comprising aforce transmitting structure andtripping means controlling said structure, said tripping meanscomprising a collapsible toggle having one link thereof connected tosaid structure, spring means for causing collapse of said toggle andactuation of said structure, means including a latch for preventingcollapse of said toggle, and means for actuating said latch to releasesaid toggle comprising a pivoted force receiving member, a pivoted forcetransmitting member, and an abutting connection between said members forcontrolling the movement of said force transmitting member in onedirection, said force transmitting member upon movement thereofactuating said force receiving member to move said latch to release saidtoggle, said toggle upon release thereof further moving said forcereceiving member in latch opening direction independently of themovement of said force transmitting member.

5. An operating mechanism comprising a force transmitting structure andtripping means controlling said structure, said tripping meanscomprising a iirst collapsible toggle having one link thereof connectedto said structure, spring means for causing collapse of said toggle andactuation of said structure, means including a latch for preventingcollapse of said toggle, and means for actuating said latch to releasesaid toggle comprising a pivoted force receiving member, a pivoted forcetransmitting member, an abutting connection between said members forcontrolling the movement of said force receiving member in onedirection, and a second collapsible toggle having one link thereofattached to said force receiving member and the other link thereofattached to said latch for locking said latch to restrain movement ofsaid first toggle, said force transmitting member upon movement thereofactuating said force receiving member to collapse said second toggle andmove said latch to release said first toggle, said first toggle uponrelease thereof further moving said latch and said force receivingmember in latch opening direction independently of the movement of saidforce transmitting member.

6. `An operating 'mechanism comprising a force transmitting structureand tripping means controlling said structure, said tripping meanscomprising a collapsible toggle having one link thereof connected tosaid structure, a first spring means for causing collapse of said toggleand actuation of said structure, means including a latch for preventingcollapse of said toggle, and means for actuating said latch to releasesaid toggle comprising a pivoted force receiving member, a pivoted forcetransmitting member, an abutment member secured to said forcetransmitting member for controlling the movement of said force receivingmember in one direction, and a second spring means biasing said forcereceiving member into engagement with said abutment member, said forcetransmitting member upon movement thereof actuating said force receivingmember against the bias of said second spring means to move said latchto release said toggle, said rst spring means upon release of saidtoggle further actuating said force receiving member in latch openingdirection against the bias of said second spring means independently ofthe movement of said force transmitting member.

7. An operating mechanism comprising a force transmitting lever, a bellcrank having one arm thereof secured to said lever, a collapsible togglehaving one link thereof connected to the other arm of said bell crank, arst spring means for causing collapse of said toggle and actuation ofsaid lever, Ymeans including a latch to lock said toggle in anover-center position, means for actuating said latch to release saidtoggle comprising a force receiving member, a force transmitting member,said members being supported for pivotal movement abouty a common axis,an abutment member secured to said force transmitting member forcontrolling the movement of said force transmitting member apredetermined distance in latch releasing direction, and a second springmeans biasing said force receiving member into engagement with saidabutment member, said force transmitting member upon movement thereofactuating said force receiving member against the bias of said secondspring means to move said latch to release said toggle, said firstspring means upon release of said toggle further actuating said forcereceiving member in latch opening direction against the bias of saidsecond spring means independently of the movement of said forcetransmitting member.

' JOHN F. CHIPMAN.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,786,727 Adam Dec. 30, 19301,814,777 Wurdack July 14, 1931

